Lol, now where did you find that photo of Cha Moi? I built that myself. I think I wrote this up once:
1. Get six holders from BritishPacific.
2. Bolt them together.
3. Get 2 pieces of shelving (support, utility) metal, L shaped, 4 foot length from the hardware store. (The kind that's drilled full of holes and about 3" in one dimension and 2" the other.)
4. cut to fit so that the 2" side can be slipped into the roll cage where the bolts that hold the bottom corners of the roll cage together are located.
5. Bolt metal onto can holders.
6. Get a narrow piece of L-shaped iron and bolt with U-bolts to the back of the roll cage, high enough to back up to the tops of the can holders. (In the process, paint some of this stuff black.)
7. Bolt on the can holders by removing the screws from the two inside lower corners of the roll cage (one at a time, please!), slipping in the first metal hardware store bar that's bolted to the can holders, and retightening the bolts, then (without letting go!) secure the top of the can holders to the 6. iron with a loose fitting zip tie.
8. Drop in your cans from the top.
9. Strap in each can with a non-hooked rachet strap (cut off excess) top to bottom and around the roll cage bars. As you rachet up the cans, the top of the can holder will be pulled INTO the rectangle made by the roll cage, thus preventing removal of the cans. The second bar will keep it from smashing your windows!
9. BEFORE assembly, figure out how you want the cans facing -- fore or aft. Has a lot to do with how easy it is to fill and empty the cans. I carry 4 gas, 1 water, 1 CO2 tank. I have them arranged so that the filler holes can be opened without moving the cans or holders. That way I can gas up without moving the cans. I also made a 13 foot super syphon so I can empty all four without dismounting or moving them.
10. You may want to remove the hinged top bar off the can holders. I did, except for the one over the CO2 bottle, which I lock down with a small padlock. Makes it SO much easier to fill and empty.
11. I raced this rig in two NVTRs so far with no failures. But still, no garantees!! I check the tension on the rachet straps at every stop. Don't make to tight or they'll bend back the bar too close to the windows. You can check the tension by just plucking the lower part of the strap, should strike a nice note! High note, too tight, dull bass, too loose.